Venlafaxine Attenuated the Cognitive and Memory Deficit in Mice Exposed to Isoflurane Alone

Post-operative cognitive dysfunction (POCD) is a common complication during the post-operative period. It affects the recovery time of the patient after surgery and the stay time in hospital, which causes a great deal of burden to patients and families emotionally and financially. However, there is no specific and effective treatment available for this disorder. Recent study indicated exposure to general anesthetics contributed to POCD by triggering gamma-amino butyric acid type A (GABA_A) receptors hyperactivities that persisted even the anesthetic compounds have been eliminated. Here, we investigated the antidepressant, venlafaxine (VLX), in a mouse model of POCD and studied whether VLX attenuated the cognitive dysfunction of mice exposed to general anesthetic, isoflurane (ISO). We found that ISO significantly induced an increased surface expression of the GABA_A receptor subunit, α5, in the hippocampus of the mice. However, VLX treatment reduced the increase in α5 subunit expression. Meanwhile, we found the expression levels of interleukin (IL)-1β, tumor necrosis factor alpha (TNF-α), and IL-6 in the brains of mice exposed to ISO were significantly increased. However, VLX could prevent the increase in these cytokines. We also investigated the memory deficit of these mice by using a Y maze behavioral test. Mice with ISO exposure showed decreased alternation performance that could be prevented by the VLX treatment. Collectively, our results here are in line with the previous findings that α5 subunit plays an important role of the formation of POCD, but VLX may be a promising candidate compound for the treatment of POCD.